Combine orange juice, orange zest, seasoning, maple syrup, brown sugar, and mustard in a small bowl. Whisk or stir to combine to form the glaze.
If you want, you can now thinly slice the ham about ¾ through. Don't cut it through completely, or the ham roast won't keep its shape.
Pour a cup of water into the bottom of the Instant Pot.
Wrap the ham with aluminum foil, and place this on top of a trivet in the pressure cooker.
Brush the brown sugar glaze on top of the ham, and make sure that the glaze drips down onto each slice.
Wrap the aluminum foil around the top of the ham, and make sure to completely seal the meat.
Then cover the Instant Pot with the lid, and pressure cook on high pressure for 10 minutes, plus an additional 2 minutes per pound.
Do a natural pressure release which takes about 15 minutes, or manually release the pressure if you prefer.
As an optional last step, you can transfer the ham to a casserole dish or baking dish. Pour the glaze that's left at the bottom of the aluminum foil packet over the ham, and bake at 200 C / 400 C for about 10-15 minutes, or until the ham is golden on top.